diff --git a/Documentation/sphinx-static/custom.css b/Documentation/sphinx-static/custom.css
index 9b08be290014..6c03dca44c82 100644
--- a/Documentation/sphinx-static/custom.css
+++ b/Documentation/sphinx-static/custom.css
@@ -83,6 +83,13 @@ div.kerneltoc li.current ul { background-color: white; }
  */
 section#the-linux-kernel-documentation p.caption { display: none; }
 
+/*
+ * Make section titles bold in the sidebar, and decrease their bottom margin to
+ * group them with their subsections.
+ */
+div.sphinxsidebar p.caption { font-weight: bold; margin-bottom: 0; }
+div.sphinxsidebar p.caption + ul { margin-top: 0; }
+
 /*
  * The CSS magic to toggle the contents on small screens.
  */